The heart of any compressed air
system is the air compressor itself. When selecting an air
compressor, the most important factors to consider are quality
and reliability. Reflected in quality and reliability are
overall cost, efficiency, and ease of maintenance. The most
cost-effective unit may not be the lowest priced. Components to
evaluate in a compressor include:

Airend:

Look at the package efficiency and
check with the manufacturer for engineering data. Evaluate
proven performance and reliability.

Cooling Systems:

Must be adequate to handle maximum
ambient operating temperature. Air-cooled compressors have
either integrally mounted or separate oil and air coolers.

Drive:

Efficiency is critical. Belt drives
are easier to maintain and provide the most flexibility in
pressure selection. Automatic belt-tensioning devices ensure
transmission efficiency and protect bearings from excess stress.

Controls:

System must be reliable, readable,
and run the compressor efficiently.

Interconnecting Piping:

Look for rigid piping with flexible
connections to eliminate leaks.

Filtration:

Performance filters protect the
compressor from contamination.

Motor:

Compare brake horsepower to nameplate
rating. Motors which go into the service factor are less
reliable. Also, TEFC motors are protected better against
contaminants than ODP motors.

Energy savings at reduced flow
requirements depend solely on the ability of the compressor
control to translate reduced air flow into lower electrical
power consumption. The chart below shows the relationship
between the full load power required for a compressor at various
air demands and common control types. It becomes apparent that
the on line-off line control (dual control) is superior to other
controls in translating savings in air consumption into real
power savings.